Graphene Quantum Dot-Based Electrochemical Immunosensors for Biomedical Applications

In the area of biomedicine, research for designing electrochemical sensors has evolved over the past decade, since it is crucial to selectively quantify biomarkers or pathogens in clinical samples for the efficacious diagnosis and/or treatment of various diseases. To fulfil the demand of rapid, specific, economic, and easy detection of such biomolecules in ultralow amounts, numerous nanomaterials have been explored to effectively enhance the sensitivity, selectivity, and reproducibility of immunosensors. Graphene quantum dots (GQDs) have garnered tremendous attention in immunosensor development, owing to their special attributes such as large surface area, excellent biocompatibility, quantum confinement, edge effects, and abundant sites for chemical modification. Besides these distinct features, GQDs acquire peroxidase (POD)-mimicking electro-catalytic activity, and hence, they can replace horseradish peroxidase (HRP)-based systems to conduct facile, quick, and inexpensive label-free immunoassays. The chief motive of this review article is to summarize and focus on the recent advances in GQD-based electrochemical immunosensors for the early and rapid detection of cancer, cardiovascular disorders, and pathogenic diseases. Moreover, the underlying principles of electrochemical immunosensing techniques are also highlighted. These GQD immunosensors are ubiquitous in biomedical diagnosis and conducive for miniaturization, encouraging low-cost disease diagnostics in developing nations using point-of-care testing (POCT) and similar allusive techniques.TU Berlin, Open-Access-Mittel - 201

Beyond DNA origami: the unfolding prospects of nucleic acid nanotechnology

Nucleic acid nanotechnology exploits the programmable molecular recognition properties of natural and synthetic nucleic acids to assemble structures with nanometer‐scale precision. In 2006, DNA origami transformed the field by providing a versatile platform for self‐assembly of arbitrary shapes from one long DNA strand held in place by hundreds of short, site‐specific (spatially addressable) DNA ‘staples’. This revolutionary approach has led to the creation of a multitude of two‐dimensional and three‐dimensional scaffolds that form the basis for functional nanodevices. Not limited to nucleic acids, these nanodevices can incorporate other structural and functional materials, such as proteins and nanoparticles, making them broadly useful for current and future applications in emerging fields such as nanomedicine, nanoelectronics, and alternative energy. WIREs Nanomed Nanobiotechnol 2012, 4:139–152. doi: 10.1002/wnan.170 For further resources related to this article, please visit the WIREs website .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90282/1/170_ftp.pd

Cell-Free Synthetic Biology Platform for Engineering Synthetic Biological Circuits and Systems

Synthetic biology brings engineering disciplines to create novel biological systems for biomedical and technological applications. The substantial growth of the synthetic biology field in the past decade is poised to transform biotechnology and medicine. To streamline design processes and facilitate debugging of complex synthetic circuits, cell-free synthetic biology approaches has reached broad research communities both in academia and industry. By recapitulating gene expression systems in vitro, cell-free expression systems offer flexibility to explore beyond the confines of living cells and allow networking of synthetic and natural systems. Here, we review the capabilities of the current cell-free platforms, focusing on nucleic acid-based molecular programs and circuit construction. We survey the recent developments including cell-free transcription– translation platforms, DNA nanostructures and circuits, and novel classes of riboregulators. The links to mathematical models and the prospects of cell-free synthetic biology platforms will also be discussed.11Yscopu

Synthetic biology: advancing biological frontiers by building synthetic systems

Advances in synthetic biology are contributing to diverse research areas, from basic biology to biomanufacturing and disease therapy. We discuss the theoretical foundation, applications, and potential of this emerging field

Biophysics of DNA based Nanosystems Probed by Optical Nanoscopy

A dynamic DNA nanosystem exploits the programmable structure and energy landscape of DNA self-assembly to encode designed processes in a fuctuating molecular environment. One type of such a dynamic system, DNA walker, is reminiscent of biological motor proteins that convert chemical energy into mechanical translocation. Typical DNA walker travels tens of nanometers at a speed orders of magnitude slower than motor proteins. Two major challenges limited the development of functional DNA walkers. First, there are no suitable characterization methods that o˙er adequate spatial and temporal resolution to extract walker kinetics. Second, no guidelines have been established for the design and development of DNA walkers with specifed properties. In this work, an enzymatic DNA walker system that integrate oligonucleotides with nanomaterials is designed. This approach takes advantage of novel optical properties of nanomaterials and sub-di˙raction imaging techniques to study the kinetics and biophysical nature of synthetic DNA walkers. Design principles are extracted from walker kinetics for constructing functional walkers that can rival motor proteins. Multiple schemes are explored to regulate the walker motility so that various behaviors can be encoded into the system. This work demonstrates novel methods to design and construct molecular systems with programmed functions, which will pave the road for creating synthetic systems with encoded behaviors from the bottom up

Toxicological response of the model fungus Saccharomyces cerevisiae to different concentrations of commercial graphene nanoplatelets

Graphene nanomaterials have attracted a great interest during the last years for different applications, but their possible impact on different biological systems remains unclear. Here, an assessment to understand the toxicity of commercial polycarboxylate functionalized graphene nanoplatelets (GN) on the unicellular fungal model Saccharomyces cerevisiae was performed. While cell proliferation was not negatively affected even in the presence of 800 mg L−1 of the nanomaterial for 24 hours, oxidative stress was induced at a lower concentration (160 mg L−1), after short exposure periods (2 and 4 hours). No DNA damage was observed under a comet assay analysis under the studied conditions. In addition, to pinpoint the molecular mechanisms behind the early oxidative damage induced by GN and to identify possible toxicity pathways, the transcriptome of S. cerevisiae exposed to 160 and 800 mg L−1 of GN was studied. Both GN concentrations induced expression changes in a common group of genes (337), many of them related to the fungal response to reduce the nanoparticles toxicity and to maintain cell homeostasis. Also, a high number of genes were only differentially expressed in the GN800 condition (3254), indicating that high GN concentrations can induce severe changes in the physiological state of the yeast.European Union’s H2020 research and innovation programme under the Marie Skłodowska-Curie grant agreements N° 691095 and N° 734873; and Junta de Castilla y Leon-FEDER under grants N° BU079U16, and N° UBU-16-B